The lateral part of the pars distalis: pars distalis (PaD), acidophilic cell (AC), basophilic cell (BC), chromophobe cell (CC), sinusoid (Sin), somatotroph cell (SC), thyrotroph cell (TC), gonadotroph
cell (GC), corticotroph cell (ACTHC).
The same attempt made by the corticotroph cells to overcome cortisol deficiency is (unsuccessfully) performed by the gonadotroph
cells, which produce high amounts of luteinizing (LH) and follicle-stimulating (FSH) hormone in response to undetectable sex hormone levels.
For comparative analysis, the 30 nonadenomatous anterior pituitary samples were processed into TMAs as well, together with 55 PIT-1-positive, 22 gonadotroph
, and 82 nonfunctioning pituitary adenomas.
Mutations of the PROP1 primarily affects thyrotroph, lactotroph, gonadotroph
, and somatotroph cells.
(1,8) Three main pathways appear relevant: a prolactin-GH-thyroidstimulating hormone (TSH) pathway regulated by transcription factor Pit-1, (9-11) a gonadotroph
pathway regulated by steroidogenic factor 1 (SF-1), (12,13) and a corticotroph pathway mediated by T-box transcription factor (Tpit).
Although most clinicians intuitively link the effect of GnRH agonists and antagonist on LH levels to that of FSH, the regulation of these two hormones in the anterior pituitary gonadotroph
cells by GnRH and other stimulus are very different.
(21-23) Endogenous GnRH is released from the median eminence of the hypothalamus, binding to receptors on the gonadotroph
, and facilitating the production and secretion of the gonadotropins luteinizing hormone (LH) and follicle-stimulating hormone (FSH) into the systemic circulation.
In this regard it is noteworthy that it has been proposed that an interaction occurs between the somatotroph and gonadotroph
hormonal axes, represented by 17-MT and GH (Holloway & Leatherland 1998, Holloway et al.
tumors usually secrete their products inefficiently and in low concentrations and, thus, very rarely cause any clinical syndrome other than sellar mass effects (3), (4).
It is possible to postulate that high PRL levels suppress LH release, both by antagonizing the hypothalamic release of GnRH and by decreasing gonadotroph
sensitivity to the latter.
In the new study, the researchers investigated by creating mice lacking insulin receptors only in the gonadotroph
. When healthy and lean, those mice appeared to do just fine.